Ignition systems for internal combustion engines



March 12, 1963 F. J. KAEHNI 3,

IGNITION SYSTEMS FOR INTERNAL COMBUSTION ENGINES Filed Nov. 12, 1959[Alllllll """I' Power Source I INVENTOIiLQ Frank .1 Kaelm/ HIS ATTOR/VEY5 United States Patent 3,081,360 IGNITION SYSTEMS FOR INTERNALCOMBUSTION ENGINES Frank J. Kaehni, Cleveland, Ohio, assignor to TheEconomy Engine Company, Youngstown, Ohio, a corporation of Ohio FiledNov. 12, 1959, Ser. No. 852,281

2 Claims. (Cl. 123148) The present invention relates generally tointernal oombustion engines and, more particularly, to ignition systemsfor suchengines. It provides a materially simplified ignition systemand, at the same time, overcomes many of the known objectionableoperating characteristics of such engines and eliminates some of themechanical requirements therefor.

In my Patents Nos. 2,866,447 and 2,866,839, granted December 30, 1958, Ihave described ignition systems for internal combustion enginesemploying a continuous spark for ignition purposes instead of the usualsingle timed spark as employed in the conventional system. In thesystems shown therein, a compact series of sparks is formed andmaintained at all times during operations in all cylinders and thesparking electrodes of the spark plugs are located so that the sparksare formed in recesses which are in communication with the cylinders orcombustion chambers. The systems which are shown and described in saidpatents are of such character as to permit the elimination of the usualtiming mechanism and the distributor.

The term continuous spark is employed in said patents and also herein todesignate a series of individual sparks for each explosion of theengine. The continuous spark, in reality, may be continuous in the sensethat a spark is maintained at the electrodes of each spark plug at alltimes during the operation of the engine, i.e., throughout the fourcycles of a four cycle engine. However, it is not necessary that thecontinuous spark function throughout each complete cycle. It is merelynecessary that a compact series of individual sparks be supplied foreach explosion and, in order to accomplish this, the power source andthe electrical connections should be such as to provide continuoussparking at the electrodes during a substantial portion of the combinedcompression and power strokes of any specific cylinder. In mypreferred-system, I maintain sparking at the electrodes of each of thespark plugs at all times and maintain a sparking condition of suchcharacter that, when peak pressure is achieved in any given cylinder, athot spark of sufficient intensity to ignite the compressed gases ispresout.

In the system disclosed in Patent 2,866,839, the individual spark plugsare arranged in parallel circuit relationship and a resistance,capacitance or reactance is present in each of the individual spark plugcircuits.

These act as current limiters to maintain the required current at eachplug; and the voltage at each plug varies with the pressure andtemperature conditions so that, when the pressure in each cylinderincreases, the power at each plug increases because of the increase involtage.

In the parallel arrangement as disclosed in Patent No. 2,866,839, if theengine is an eight cylinder engine and a current of approximately 2milliamps per cylinder is required, the high voltage power supply mustsupply 16 milliamps at a voltage slightly higher than the highestvoltage necessary for peak compression sparking through the currentlimiters in series with each plug. I have found that a seriesarrangement of all of the plugs can be employed in this system and that,when employed, it is only necessary that the power supply a total of 2milliamps at a voltage slightly higher than is required for the parallelcircuit of Patent No. 2,866,839. I have also found 2 that, by employingthis series circuit arrangement, the current limiters for each plugcircuit may be eliminated.

In carrying out my present invention, special spark plugs are requiredsince it is necessary that each has two insulated electrodes. Theelectrodes of adjacent plugs are, of course, connected in seriesrelationship with respect to the high voltage ignition circuit. By thisarrangement, the current remains substantially equal throughout theentire circuit, but the voltage varies in individual parts according tothe resistance of each part of the circuit. The resistance in thecircuit for that plug which is about to fire is, of course, increased asthe pressure at such plug increases.

In the accompanying drawings, I have shown, for purposes of illustrationonly, a preferred embodiment of my invention and several modificationsthereof.

In the drawings:

FIGURE 1 shows a system in accordance with my invention and in which atransistor is employed in the primary circuit and in which the sparkplugs for the eight cylinders are arranged in series circuitrelationship in the secondary circuit;

FIGURE 2 is a partial view somewhat similar to FIG- URE 1 except that itembodies several modified features; FIGURE 3 is a view illustrating therelationship between the plug, ignition chamber and main combustionchamber and illustrating somewhat diagrammatically the type of sparkplug required for the circuit of my invention.

In the embodiment shown in FIGURE 1, the power source comprises abattery 2, a transistor indicated generally by the reference character3, and a transformer indicated generally by the reference character 4.The high voltage current for ignition purposes is supplied by thesecondary 5 of the transformer 4 to the spark plugs 6, 7, 8, 9, 10, 11,12 and 13, these plugs being arranged in series relationship. One sideof the secondary coil 5 is connected to one electrode of the spark plug6 and the other electrode of said spark plug is connected to anelectrode of the adjacent spark plug 7. This same arrangement iscontinued through the circuit and one electrode of the plug 13 isconnected to the other side of the secondary. The circuit may begrounded, as indicated at 14 to serve as a regulator for the voltagessupplied. The shell of each spark plug likewise may be grounded ifdesired. The shell of each plug, however, is not connected electricallyto either of the two electrodes, as will be pointed out more fullyhereinafter.

Referring to the power supply illustrated, the positive terminal of thebattery is connected by a lead 20 to the emitter 21 of the transistor.The current fiows through the emitter to the collector 22 and thence, bymeans of the connecting lead 23, to one side of the primary winding 24of the transformer. The current rapidly reaches its maximum valuedepending upon the base bias current setting of the resistor 25 in thetransistor circuit and upon the fact that the voltage on the baseterminal of the transistor is negative in respect of the emitter. Theother side of the primary coil 24 is connected by a lead 26 to thenegative terminal of the battery and it is also connected to one end ofa control winding 27 in the primary circuit. The other side of thiscontrol winding is connected to the resistor 25. When the magnetic fluxin the core has reached its maximum value, the flux change becomes zeroand the induced voltages in the windings are zero. This causes the basebias current from the control winding 27 to begin to reverse and startthe negative or cut-off portion of the current cycle. With a decreasingflux in the core of the transformer, reverse voltages are induced andthis rapid collapse of flux in the core produces the high peak voltagesin the secondary 5 and, in turn, produces the rapid recurring spark-s atthe spark plugs. A capacitor 28 is included in the transistor circuit toprotect it against excessive voltage. Another capacitance 29 is includedin the circuit also as a protective measure.

Referring now to FIGURE 3, I have illustrated the relationship between acylinder, its communicating recess or ignition chamber, and its sparkplug. I have also shown in FIGURE 3, somewhat diagrammatically, .thetype of spark plugs required for this invention. As shown in this view,the recess or ignition chamber 30 is in communication with the maincombustion chamber 31 of the cylinder. An individual piston 32 isslidably mounted in each cylinder and has associated therewithconventional inertia means external of the cylinders for continuingmovement of the pistons in rotation according to a regular firing order.The spark plug 33 has its lower end threaded so that it can be mountedin the threaded upper end of the ignition chamber 30. The spark plug hastwo electrodes 34 and 35 which extend downwardly into the ignitionchamber 30 and sparking takes place between the inner ends of theseelectrodes. The other ends thereof extend through an insulator 36 andone electrode is connected to the power source and the other to theadjacent plug by leads 37 and 35. These electrodes must be insulatedfrom each other to a point adjacent the inner ends thereof and must beinsulated from the side walls of the ignition chamber in order topreclude spark-over from the electrodes to the adjacent wall. As shownin FIGURE 3, there is an insulator .36 between the electrodes andbetween the electrodes and the adjacent wall and the insulator extendsdownwardly into the ignition chamber to a slight extent in order toprevent sparking to take place only between the electrodes and thechamber side walls.

Referring now to FIG. 2, I have shown here a partial view illustrating amodification of the circuit shown in FIGURE 1. In FIGURE 2, thetransformer 4 is similar to the transformer 4 of FIGURE 1 and thebattery and transistor circuits are the same as shown in FIG- URE 1.Therefore, they have not been illustrated in FIGURE 2. The secondary 5'is divided into two coils and one end of each coil is connected toground, as illustrated at 40. The plugs 6' to 13', inclusive, and theground 14' are the same as the parts carrying corresponding numbers inFIGURE 1. In this circuit, however, I have shown a resistance 41 in thesecondary circuit which may be used for the purpose of limiting thecurrent in the secondary to any desired value.

In the circuit of FIGURE 2, I have also shown at capacitance 42 which,if desired, can be embodied within the transformer case. Thiscapacitance is for the purpose of providing resonance in the circuit. Agreater voltage per turn can be obtained from the transformer when itsinductive and capacity reactance are equal; that is, when the circuit isproperly tuned. Resonance can be obtained in various ways in addition tothe manner illustrated in FIGURE 2.

It will be readily apparent from what has been stated above that thepresent invention provides a simple, inexpensive ignition system forinternal combustion engines and that, due to the pressure conditionsprevailing in the various cylinders, the plugs of which are arranged inseries, suitable and accurate timing can be obtained Without thenecessity of a usual distributor and timing mechanism and that a hotspark will be formed in any cylinder under pressure at the right time todeliver the greatest amount of power for the amount of fuel consumed.

The present invention is not limited to the embodiments disclosed hereinas it may be otherwise embodied within the scope of the appended claims.

I claim:

1. An ignition system for an internal combustion engine having aplurality of cylinders providing a plurality of combustion chambers andpistons reciprocating in said cylinders, comprising an ignition chamberfor each cylinder, each ignition chamber communicating with thecombustion chamber of a cylinder, a pair of permanently spacedelectrodes within each ignition chamber and spaced from thecommunicating combustion chamber, a source of high potential current,and electrical conductors directly connecting all of said pairs ofelectrodes in series with each other to said source of high potentialcurrent.

2. An ignition system according to claim 1 in which said source producesan oscillating high potential current and in which a capacitor isconnected across said source to tune the electrical circuit to oscillatein resonance.

References Cited in the file of this patent UNITED STATES PATENTS1,319,330 Hagan Oct. 21, 1919 2,324,923 Grow July 20, 1943 2,436,905Short Mar. 2, 1948 2,811,676 Smits Oct. 29, 1957 2,866,839 Kaehni Dec.30, 1958 FOREIGN PATENTS 77,286 Netherlands Sept. 15, 1954 29,255 GreatBritain Dec. 14, 1909 798,455 Great Britain July 23, 1958 n.. W -i

1. AN IGNITION SYSTEM FOR AN INTERNAL COMBUSTION ENGINE HAVING APLURALITY OF CYLINDERS PROVIDING A PLURALITY OF COMBUSTION CHAMBERS ANDPISTONS RECIPROCATING IN SAID CYLINDERS, COMPRISING AN IGNITION CHAMBERFOR EACH CYLINDER, EACH IGNITION CHAMBER COMMUNICATING WITH THECOMBUSTION CHAMBER OF A CYLINDER, A PAIR OF PERMANENTLY SPACEDELECTRODES WITHIN EACH IGNITION CHAMBER AND SPACED FROM THECOMMUNICATING COMBUSTION CHAMBER, A SOURCE OF HIGH POTENTIAL CURRENT,AND ELECTRICAL CONDUCTORS DIRECTLY CONNECTING ALL OF SAID PAIRS OFELECTRODES IN SERIES WITH EACH OTHER TO SAID SOURCE OF HIGH POTENTIALCURRENT.